Bats

Bats are essential parts of Earth’s environments and perform services valuable to humans. Research by USGS scientists shows that insect-eating bats—through their free pest-suppression services—save farmers at least $3 billion each year. Many bat populations are declining due to factors such as habitat loss and disease. Recent growth in wind-energy development brought the unexpected consequence of bat susceptibility to wind turbines. USGS science aims to understand and reduce bat fatalities and injuries at wind turbines through several integrated research strategies.

Can We Make Wind Power Compatible with Wildlife?

This story is a case study on wind energy and bats in Hawaii that communicates the impact and value of USGS science to people and the environment. It focused on a portfolio of research that addresses the mortality of bats at wind energy facilities and describes the approach that USGS scientists are taking to develop “smart solutions” to help reduce the risks, as well as the costs, of domestic energy development.

Understanding Risks

USGS research focuses on understanding underlying causes of bat fatalities at wind turbines. Discovering why bats die at turbines may be the shortest path to understanding how to fix the problem. USGS research led to new insights, such as the “tallest-tree”, “mistaken-tree”, and “mating” hypotheses, as well as a framework to help guide research into bat susceptibility.

USGS scientists pioneered a suite of monitoring methods for observing bats at operating wind energy facilities. The resulting observations expanded understanding of how bats interact with wind turbines under a variety of conditions, situations, and experimental manipulations. Combined with similar experiments in natural environments, this USGS research sheds new light on why bats approach turbines and how they can be kept away.

Measuring Impacts

USGS and our research partners are experimenting with different configurations of thermal surveillance cameras and video-processing software to optimize the ability to determine strikes and risky behaviors. These new methods may help predict risk, as well as efficiently compare mitigation measures, by providing the specific times, locations, and conditions when bats dangerously interact with wind turbines.

Developing Solutions

USGS scientists are working to develop innovative tools and technologies to reduce injuries and fatalities from wind turbines. Current efforts involve developing and testing devices that could be installed on wind turbines to provide a consistent and energy efficient way of reducing bat fatalities.

Most bats affected by wind turbines hunt insects in the dark using echolocation. USGS scientists are working with research partners funded by the Department of Energy to test a method of preventing bats from approaching and dying at turbines by deterring them with high-frequency sounds. Testing such ultrasonic deterrent devices is now feasible with monitoring methods recently developed through USGS research.

Collaborative research by scientists from USGS, University of Hawai'i at Hilo, and Bat Research and Consulting discovered a previously underappreciated sensory modality in bats—dim ultraviolet vision. Prior USGS-led research indicated bats might "see" turbines as trees, so dim ultraviolet light flickered on turbines has potential to keep bats away yet be invisible to humans and birds. The group tested this concept by illuminating trees in areas frequented by Hawaiian hoary bats (Lasiurus cinereus semotus), an endangered subspecies affected by wind turbines, and saw evidence that bats stayed away. The next stage of this research involves experimentally illuminating wind turbines to try and reduce bat fatality.